By Kathy Rowe

The botanical term “mast year” is defined as a year when a tree produces an overabundance of fruit. That fruit includes seeds, nuts, berries, apples, etc. To be specific, nut and seed trees are considered “hard mast” and berries are “soft mast.”

I know for a fact that 2023 has been a hard mast year because of the enormous number of acorns on my lawn from the oak trees that live there. We have an Ohio Buckeye tree in the front yard that has dropped more nuts this fall than any fall I can remember. On my walks through the neighbourhood the number of tree nuts on the sidewalks is crazy. We can add tree nuts this year to our list of tripping hazards while on leisurely walks.

The book The Hidden life of Trees, by Peter Wohlleben, gives some really insightful information about how trees communicate with each other and why they behave the way they do. It is explained in the book that in a particular year deciduous trees purposefully produce an abundance of fruit simultaneously to provide more fruit than the area wildlife (deer, squirrels) can consume. In these years the wildlife will gorge on the food, fatten up, and then procreate their species.

The trees, the book goes on to explain, are actually not doing this to benefit the animals, they are really protecting their own species because in a mast year there will still be fruit on the ground that will sprout more trees the following spring. It is simply not possible for the herbivores to devour all of the fruit that is produced.

The trees will then take a break for the next few years and produce less fruit. This, of course,

forces the animals to pick the tree bare until another hard mast year comes along. Peter Wohlleben writes: “If they don’t bloom every year, then the herbivores cannot count on them. The next generation is kept in check because over the winter the pregnant animals must endure a long stretch with little food, and many of them will not survive.”

While looking for more information on this topic, I posed my questions on the website and got this response: “The full explanation of the phenomenon of mast years remains a mystery. One of the most perplexing aspects of mast years is the question of how trees of a particular species in a particular area coordinate their mast years.

“Naturalists have postulated that there may be chemical signals (either airborne or through soil/root fungal connections) between the trees in an area, but this has not been proven scientifically. What is sure is that all of the trees of one or more species within a fairly large geographic area (i.e. Toronto) have achieved a synchrony and a mast year for 2023.”

The response also said that in a mast year an oak tree can produce almost 10,000 acorns. Happy raking!